In videoconferencing systems, multiple videoconferencing servers may be used to host videoconferences. For example, for efficiency reasons a large capacity conferencing infrastructure might be split across multiple separate units or servers. The total capacity needed at any given time across multiple active conferences might exceed that of an individual box, or it might be that it is necessary for the hosting organisation to be able to take different units out of service (for instance for software upgrades) without ending the service completely.
When a new participant, or user, dials into a videoconferencing system, their call is generally connected to the nearest videoconferencing server (or node). This may be the geographically nearest node to the user's videoconference equipment, or it may be the nearest node in terms of network latency.
The decision on which node to connect an incoming call to may also be based on load balancing. For instance, a call routing system that can place a call on one of several conferencing servers might choose to place new calls on the servers according to a “round robin” scheme whereby (for instance in the case of a 2 server system) the first call might be placed on box 1, the second on box 2, the third call on box 1, and so on.